Conventionally, based on a pre-obtained predicted value of a satellite orbit, beam direction of an antenna is controlled by controlling drive axes of the antenna to track a satellite.
A three-axis control antenna device disclosed in the patent literature 1 sends input to drive inputs of two axes among drive inputs of three axes that are driven and controlled individually when a beam direction of an antenna is at an angle less than a set elevation angle, and sends inputs to all drive inputs of three axes when the beam direction is greater than or equal to the set elevation angle. After switching to three-axis driving, the three-axis control antenna device sends a value of a particular axis obtained by calculating present values of the three axes to the drive input of the particular axis among the three axes.
A satellite tracking antenna driving and controlling device disclosed in patent literature 2 calculates a program prediction angle oriented toward a satellite at each predetermined time interval using a program tracking method that tracks a satellite by driving an antenna of the azimuth/elevation mount method or the X/Y mount method based on a pre-obtained orbit prediction information of a satellite. In addition, when a satellite is predicted to pass in the vicinity of zenith based on the program prediction angle, X/Y coordinates are chosen as coordinates used in an interpolation process to calculate a program command angle directing to a satellite at a time interval shorter than the predetermined time interval.